Coherent continuous-wave dual-frequency high-Q external-cavity semiconductor laser for GHz-THz applications

Romain Paquet (1) , Stéphane Blin (1, 2) , Mikhael Myara (1, 2) , Luc Le Gratiet (3) , Mohamed Sellahi (1) , Baptiste Chomet (1, 2) , Gregoire Beaudoin (3) , Isabelle Sagnes (3) , Arnaud Garnache (1, 2)

1 IES - Institut d’Electronique et des Systèmes
2 TéHO - Térahertz, hyperfréquence et optique
3 LPN - Laboratoire de photonique et de nanostructures

We report a continuous-wave highly-coherent and tunable dual-frequency laser emitting at two frequencies separated by 30 GHz to 3 THz, based on compact III–V diode- pumped quantum-well surface-emitting semiconductor laser technology. The concept is based on the stable simul- taneous operation of two Laguerre–Gauss transverse modes in a single-axis short cavity, using an integrated sub- wavelength-thick metallic mask. Simultaneous operation is demonstrated theoretically and experimentally by recording intensity noises and beat frequency, and time- resolved optical spectra. We demonstrated a >80 mW out- put power, diffraction-limited beam, narrow linewidth of <300 kHz, linear polarization state (>45 dB), and low in- tensity noise class-A dynamics of <0.3% rms, thus opening the path to a compact low-cost coherent GHz to THz source development.

Domaines: Optique / photonique

Romain Paquet, Stéphane Blin, Mikhael Myara, Luc Le Gratiet, Mohamed Sellahi, et al.. Coherent continuous-wave dual-frequency high-Q external-cavity semiconductor laser for GHz-THz applications. Optics Letters, 2016, 41 (16), pp.3751-3754. ⟨10.1364/OL.41.003751⟩. ⟨hal-01528403⟩